Air Force Staff Sgt. Luis Walker, second from right, and others leave his trial at Joint Base San Antonio-Lackland on Friday, July 20, 2012, after he was convicted on all counts of illicit sexual contact with 10 women in basic training.

Photo By Jerry Lara/San Antonio Express-News

U.S. Air Force Staff Sgt. Luis A. Walker arrives from a lunch break during his court martial at Lackland Air Force Base, Monday, July 16, 2012. Walker, a former training officer, is charges with illicit sexual contact with 10 female trainees. He is facing 28 counts including rape and is one of 12 instructors under investigation.

Photo By Jerry Lara/San Antonio Express-News

U.S. Air Force Staff Sgt. Luis A. Walker arrives from a lunch break during his court martial at Lackland Air Force Base, Monday, July 16, 2012. Walker, a former training officer, is charges with illicit sexual contact with 10 female trainees. He is facing 28 counts including rape and is one of 12 instructors under investigation.

Photo By John Davenport/San Antonio Express-News

Air Force Staff Sgt. Luis Walker (foregrund) arrives for the fourth day of his trial at Joint Base San Antonio-Lackland on Friday, July 20, 2012. Walker, a boot-camp instructor, is charged with illicit sexual contact with 10 women in basic training. If found guilty, he could face a life sentence.

Photo By John L. Mone/ASSOCIATED PRESS

TIMELINE: The sex abuse scandal centered at Joint Base San Antonio-Lackland has become the worst in Air Force history with 33 basic training instructors under investigation for allegations of misconduct with 63 recruits and technical training students. The following photos depict the still-unfolding investigation.

Photo By William Luther/San Antonio Express-News

March 2, 2012: Air Force trainees at Lackland Air Force Base listen as officials explain to them about sexual misconduct and their responsibilities to report it.

Photo By Lisa Krantz/SAN ANTONIO EXPRESS-NEWS

April, 2012: Staff Sgt. Peter Vega-Maldonado, 32, pleaded guilty to two charges stemming from his relationship with a 21-year-old airman he supervised in basic training. In exchange for a reduced sentence, he agreed to testify against two other trainers he said had illicit relationships with women. The judge gave Maldonado 90 days in jail, 30 days hard labor while restricted to the base, reduction from staff sergeant to airman and forfeiture of $500 a month pay for four months. Read more: Two more Lackland AFB instructors implicated in sex scandal

Photo By COURTESY PHOTO

June 20, 2012: Lt. Col. Mike Paquette lost his job as commander of the 331st Training Squadron at Joint Base San Antonio-Lackland, where most of the accused instructors had worked. He had led the 331st Training Squadron for two years. Read more: Training boss ousted in Lackland sex scandal

Photo By Billy Calzada/Associated Press

July 20, 2012: Air Force Staff Sgt. Luis Walker arrives for the fourth day of his trial at Lackland Air Force Base in San Antonio. Walker was accused of sexually assaulting 10 basic trainees, with charges ranging from rape and aggravated sexual assault to obstructing justice and violating rules of professional conduct. Read more: Staff Sgt. Walker found guilty on all charges of sexual misconduct

Photo By Tom Reel/San Antonio Express-News

July 21, 2012: Staff Sgt. Luis A. Walker is taken away in chains from the 37th Training Wing Headquarters after sentencing. Walker, called a "sexual predator" by Air Force prosecutors, was given 20 years in prison. Read more: 'Sexual predator' gets 20 years at Lackland trial

August 1, 2012: Tech Sgt. Christopher Smith, 33, was convicted on two of four counts of misconduct with basic trainees and sentenced to 30 days in jail and a reduction in rank to airman first class, a penalty that will permit him to remain in the Air Force. Read more: AF trainer given 30 days behind bars, loss of rank

Photo By William Luther/William Luther/wluther@express-news.net

August 10, 2012: Col. Glenn Palmer lost command of the 737th Training Group, which trains more than 35,000 airmen a year at Lackland. Read more: Lackland training chief is ousted

August 22, 2012: Maj. Gen. Margaret Woodward submitted the Command Directed Investigation, which took a deeper and wider look at basic military training, to AETC Commander Gen. Edward Rice. Her recommendations will become an important blueprint for actions that will be implemented throughout basic training as well as technical training. Read more: Major general to investigate ‘systemic issues'

Photo By COURTESY/USAF

Sept. 4, 2012: After a little more than a year on the job, Air Force Col. Eric Axelbank stepped down as head of a training wing here that has been rocked by a growing sex scandal. The command change occurred one day before another instructor, Master Sgt. Jamey Crawford, goes on trial on charges of having sex with a trainee. Read more: Col. Axelbank exits Lackland for the Pentagon

Photo By Jerry Lara/San Antonio Express-News

Sept. 10, 2012: U.S. Air Force Staff Sgt. Kwinton Estacio arrives for the start of his court marshal at Lackland Air Force Base. Estacio was initially tried on charges that he sexually assaulted a female basic training student, violated a no-contact order and asked several trainees to lie about his contact with them. Read more: Lackland sergeant pleads guilty to less serious charges

Photo By Tom Reel/San Antonio Express-News

Sept. 12, 2012: Staff Sgt. Kwinton Estacio is led away from the 37th Training Wing Headquarters after sentencing in his trial at Joint Base San Antonio-Lackland. He was sentenced to one year in prison after pleading guilty to charges of obstruction and having sex with a trainee in violation of Air Force conduct rules. Read more: Former Lackland trainer receives 1-year sentence

Photo By Billy Calzada/San Antonio Express-News

Sept. 21, 2012: Col. Deborah Liddick marches with military drill
instructors during her change-of-command ceremony at JBSA-Lackland. The
fourth woman to oversee the Air Force's boot camp since 1996, she takes
over amid an investigation that is scrutinizing 33 basic training
instructors for misconduct. Read more: Woman now heads AF training at Lackland

Sept. 21, 2012: Col. Deborah Liddick, new commander of Air Force basic training at JBSA-Lackland, is applauded by by presiding officer and commander of the 37th Training Wing Col. Mark Camerer during a change-of-command ceremony.

Photo By Marvin Pfeiffer/ Express-News

Sept. 24, 2012: Staff Sgt. Jason Manko (right) is led from the courthouse to a waiting pickup on Joint Base San Antonio-Lackland after being sentenced to 45 days in jail and another 30 days of hard labor on the base for having an illicit relationship with a female trainee. Read more: Lackland trainer gets 45 days in jail in sex case

Photo By Jerry Lara/San Antonio Express-News

Oct. 2, 2012: U.S. Congresswomen from California, members of the House Armed Services Committee, Loretta Sanchez (from left), Jackie Speier and Susan Davis hold a press conference outside Lackland Air Forc e Base. The committee members met with personnel at the base to investigate the ongoing sex scandal. Read more: Lackland's ‘culture' blamed for scandal

Nov. 14, 2012: Gen. Edward Rice Jr. and Maj. Gen. Margaret Woodward met with the media at a press conference in the Pentagon as Col. Steve Clutter stands nearby to field questions. The commanders met with reporters to outline the results of an investigation into sexual misconduct among basic training instructors at Joint Base San Antonio-Lackland. Read more: Lackland leaders cited in scandal

Photo By BOB OWEN/San Antonio Express-News

Nov. 24, 2012: Former Air Force instructor Staff Sgt. Craig LeBlanc, center, who was facing 52 years in prison on charges of misconduct with three trainees, threatened to jump from a local overpass after becoming overwhelmed by his legal problems and travel restrictions. Read more: Lackland instructor's legal woes cited in apparent suicide tries. He remained in the Joint Base San Antonio-Lackland lockup after a hearing Dec. 4 in which the Air Force said he committed four new violations. Read more: Lackland trainer jailed after release

Jan. 8, 2013: Air Force Tech. Sgt. Jaime Rodriguez, middle, who is accused of rape, forcible sodomy and adultery while assigned to the Lake Jackson recruiting office from August 2008 to November 2011, arrives for an evidentiary hearing at Joint Base San Antonio-Lackland. Read more: Air Force recruiter pursued girl for sex

Photo By Susan Biddle

Jan. 23, 2013: House members sharply criticized two Air Force generals for a culture that allowed pervasive sexual abuse of recruits at Joint Base San Antonio-Lackland, and for “significant” delays in reporting the crimes. Lawmakers from both parties took turns at a congressional hearing voicing their displeasure and pressed the generals about steps the Air Force is taking to stop sexual abuse. Technical Sergeant Jennifer Norris wipes a tear as she testifies during the hearing. Read more: Panel criticizes handling of Lackland abuse

Photo By Jerry Lara/San Antonio Express-News

Jan. 31, 2013: A day after jurors cleared Staff Sgt. Donald Davis of the most serious charges against him, he was sentenced to three months of hard labor and a bad conduct discharge for having sex with a trainee in technical school. Read more: Air Force instructor sentenced to hard labor

Photo By Billy Calzada/San Antonio Express-News

Feb. 14, 2013: Air Force Staff Sgt. Craig LeBlanc, in chains, is led from a JBSA Lackland courtroom after being sentenced to 2 1/2 years after he was found guilty on all but one of nine charges that included a 2011 tryst with a recruit. Facing a battery of allegations that included sexually assaulting a woman, he was at risk of going to prison for 52 years. Read more: Lackland trainer gets prison for sexual misconduct

March 16, 2013: Air Force Staff Sgt. Eddy Soto got four years in prison and a dishonorable discharge after being found guilty of raping an airman he'd led in basic training. Soto, 30, is only the second trainer at Joint Base San Antonio-Lackland to be convicted of rape since trials began last spring in the growing instructor misconduct scandal. Staff Sgt. Luis Walker was given 20 years in July. Read more: Lackland trainer handed 4 years in rape

March 21, 2013: Former Air Force basic training instructor Master Sgt. Jamey Crawford was given seven months in jail, two months' hard labor and a bad-conduct discharge for having sex with two women and later lying to investigators about it. Read more: Trainer gets 7 months in Lackland scandal

April 2, 2013: Staff Sgt. William Romero was given 30 days' hard labor, restricted to Joint Base San Antonio-Lackland another 30 days and reduced to airman after pleading guilty to charges that he had illicit relationships with four women and committed adultery. Read more: Lackland trainer, an Iraq vet, gets 60-day sentence

April 24, 2013: Tech. Sgt. Bobby Bass, who faced up to 33 years in prison, was convicted on multiple counts of misconduct with recruits four years ago at Joint Base San Antonio-Lackland and sentenced to six months in jail and a reduction in rank by a single stripe. He was acquitted by the jury of two officers and four NCOs of a rape charge involving an airman while in Kyrgyzstan. Read more: NCO gets 6 months in abuses at Lackland

May 2, 2013: Staff Sgt. Emily Allen, who pleaded guilty to having sex with a recruit, was sentenced to three months in jail, 30 days' hard labor and reduced to airman first class. The Air Force could move to discharge her after she is released from jail. Read more: Female Lackland trainer gets jail sentence

Photo By JOHN DAVENPORT/SAN ANTONIO EXPRESS-NEWS

May 22, 2013: The Air Force says basic training instructor Michael Wladischkin had improper relationships with seven women in technical training on Joint Base San Antonio-Lackland. He faces an Article 32 evidentiary hearing Wednesday, May 22 at Joint Base San Antonio-Randolph on allegations of indecent acts, assault, adultery and unprofessional relationships with technical training students.

Photo By Scott M. Ash/U.S. Air Force

June 7, 2013: Maj. Gen. Margaret Woodward takes over as the head of the Air Force's sexual response. She replaces Jeffrey Krusinski, a lieutenant colonel who was arrested and charged with sexual battery. Read more: Lackland critic to target AF sex abuse

Photo By SAN ANTONIO EXPRESS-NEWS

April 21, 2014: Military judge Col. Donald Eller Jr. found Airman 1st Class Nathan Wilson-Crow, a photographer, guilty of four charges and five specifications of misconduct, one of which carried a possible 15-year prison sentence. Wilson-Crow was tried making sexual contact and exposing himself to at least two girls from O'Connor High School at a youth camp in April 2013. Read more: Airman guilty of some charges in Lackland sex case

Photo By San Antonio Express-News / File photo

September 1, 2014: Former Staff Sgt. Luis Walker, given 20 years in the Air Force's worst sex scandal, dies in a Kansas City, Mo., hospital. He hanged himself in a prison cell at the U.S. Disciplinary Barracks.

Photo By Express-News file photo

September 9, 2014: Following an analysis of instructor misconduct at Lackland, the Government Accountability Office reports that six recommendations have not been implemented, including one to increase the number of training instructors to 528. Read more: Changes driven by Lackland scandal not complete

Photo By JERRY LARA/San Antonio Express-News

January 29, 2015: A jury finds veteran Air Force Master Sgt. Michael Silva guilty of raping a recruit he was charged with training at Joint Base San Antonio-Lacklandin 1995. He was found guilty of twice raping the recruit, and also raping a third woman, a member of the military, in Wyoming during February 2007.

SAN ANTONIO — A former Air Force basic training instructor who was found guilty of rape and other sexual misconduct charges two years ago at Joint Base San Antonio-Lackland died Sunday after hanging himself in his prison cell, Air Force officials said.

Airman Basic Luis Walker, 28, was found in his cell Friday at the U.S. Disciplinary Barracks on Fort Leavenworth, Kan. He was taken to a Kansas City, Missouri, hospital, where he died Sunday night..

The Disciplinary Barracks did not respond to emails or phone calls, but the Air Education and Training Command said Tuesday it had been notified of his death.

“We are aware of Airman Basic Walker's passing and our thoughts are with the Walker family during this difficult time,” said Col. Sean McKenna, a training command spokesman.

Walker was a key figure in a basic training scandal at Joint Base San Antonio-Lackland, where 35 instructors have been investigated for misconduct with 69 recruits and technical school students.

Walker was given 20 years in prison, the second-longest sentence handed down in 29 trials so far at Lackland, for a long list of crimes involving female recruits he was charged with training. He was busted to airman basic and labeled a sexual predator by prosecutors.

A staff sergeant, Walker had illicit relationships with 10 women in basic training and some in units he oversaw. Some witnesses described him as sadistic and manipulative, an instructor who used his power to obtain sexual favors from recruits.

A jury handed down the sentence July 21, 2012, after finding him guilty of seven charges and 28 specifications of misconduct, including rape. He could have been given up to 40 years in prison.

His role in the scandal helped drive a training command investigation. The probe found a broken command culture and a gap in leadership that contributed to the sexual-assault scandal. It said leaders were insulated from training and that barriers “at nearly every level” limited the flow of information about instructor misconduct.